Mount Prospect, Illinois 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

963
FXUS63 KLOT 262326
AFDLOT

Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
626 PM CDT Tue May 26 2026

.KEY MESSAGES...

- Generally above normal temperatures (highs in the 80s) and
  dry conditions are expected through early next week. Onshore
  winds will keep temperatures cooler near Lake Michigan each
  day (60s-70s).

- Backdoor cold fronts will lead to cooler conditions (60s and
  70s) extending farther inland late Wednesday into Thursday and
  potentially again over the weekend.

&&

.DISCUSSION...
Issued at 217 PM CDT Tue May 26 2026

A mid-level ridge axis continues to reside across the southern
Great Lakes which is maintaining generally tranquil weather
conditions. Despite the widespread cirrus coverage overhead,
temperatures continue to warm into the lower to mid-80s which is
just about at their peak for today. That said, a lake breeze is
developing near the lake and will begin to ooze inland over the
next few hours resulting in locally cooler temperatures near
the lake.

Heading into tonight, the ridge axis will begin to move east of
the area as the broad trough over Ontario digs into the
northern Great Lakes. At the same time, the low center over
southwest IL and eastern MO will continue to lift towards the
area tonight. Associated with this low are some scattered
showers and a few thunderstorms, but their coverage should
weaken as the low approaches due to the drier air across
northern and northeast IL and northwest IN. However, there is
still a 15-20% chance for an isolated shower or two to brush our
southern CWA (namely areas along and south of US-24) overnight.
Otherwise, dry conditions can be expected with light and
variable winds and mild temperatures in the lower to mid-60s.

By Wednesday the aforementioned surface low will begin to drift
east across central IL and IN as a cold front begins to race
southward out of WI and northern Lake Michigan. While a few
showers (and perhaps and isolated rumble of thunder) may linger
along/south of US-24, mostly dry conditions are expected across
the rest of the area. The cold front is expected to move
through northern IL and northwest IN late Wednesday afternoon
and evening which will result in quickly cooling temperatures in
its wake, especially near the lake. Given the late arrival of
fropa, highs on Wednesday look to still be able to reach into
the lower to possibly middle 80s inland but prevailing onshore
winds will keep lakeside temperatures notably cooler in the 60s
to around 70. However, if the front arrives faster than forecast
then highs could end up being a few degrees cooler areawide.
Regardless, the frontal passage looks to be mostly dry though
there is still a 15-20% chance for an isolated shower or
thunderstorm to develop near the IL-WI line.

In addition to the cooling temperatures, the front will also
bring breezy north-northeast winds to the area with gusts
upwards of 20-25 mph Wednesday evening through Thursday. With
the onshore wind direction the winds will also result in
building waves and an increased risk for rip currents on Lake
Michigan. Therefore, dangerous swimming conditions are forecast
Wednesday night through Thursday.

High pressure is expected to build back into the Great Lakes
Wednesday night through weeks end which will result in dry and
tranquil weather conditions. Though, persistent northeast winds
do look to keep temperatures more in the seasonable range with
daily highs in the upper 70s to lower 80s (60s near the lake),
especially on Thursday, and overnight lows in the 50s through
next weekend.

Yack

&&

.AVIATION /00Z TAFS THROUGH 06Z THURSDAY/...
Issued at 626 PM CDT Tue May 26 2026

There are no key concerns for the 00Z TAF period:

SE winds below 10 kt this evening will go light and variable
tonight. Winds will establish a NE direction by mid-morning
Wednesday moving at less than 10 kt through the afternoon, and
closer to 10 kt during the evening. Expect VFR throughout the
period.

Doom

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...Air Quality Alert until 6 AM CDT Thursday for ILZ005-ILZ006-
     ILZ012-ILZ013-ILZ020-ILZ021-ILZ103-ILZ104-ILZ105-ILZ106-
     ILZ107-ILZ108.

     Beach Hazards Statement from Wednesday evening through late
     Thursday night for ILZ006-ILZ103-ILZ104.

IN...Air Quality Alert from midnight tonight to midnight CDT
     Wednesday night for INZ001-INZ002-INZ010-INZ011.

     Beach Hazards Statement from late Wednesday night through late
     Thursday night for INZ001-INZ002.

LM...Small Craft Advisory from 10 PM Wednesday to 10 PM CDT
     Thursday for the IL nearshore waters.

     Small Craft Advisory from 4 AM Thursday to 1 AM CDT Friday for
     the IN nearshore waters.

&&

$$

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